Holographische Abbildung nicht-kristalliner organischer und biologischer Makromoleküle mit Elektronenpunktquellen

In dieser Arbeit wurde an der Weiterentwicklung einer neuen Methode zur Strukturaufklärung von Makromolekülen gearbeitet. Holographie mit niederenergetischen Elektronen ist eine Mikroskopietechnik, die ohne Linsen und aus Linsen resultierenden Fehlern arbeitet. Hologramme können mit einer nominellen Vergößerung von M > 106 aufgenommen werden. Eine ultrascharfe Wolframspitze liefert dabei die zur Holographie benötigte kohärente Strahlung. Die Elektronenquelle wird in einem Elektronen-Projektionsmikroskop bis auf Abstände < 1 mm an ein semitransparentes Objekt angenähert. Ein Teil der aus der Punktquelle emittierten Wellenfunktion eines Elektrons wird an dem Objekt gestreut (Objektwelle). Dieser interferiert mit dem ungestreuten Anteil der Wellenfunktion (Referenzwelle) und es entsteht ein Hologramm. Um daraus Informationen über die Lage der Streuzentren zu gewinnen, muß die Wellenfront in der Objektebene rekonstruiert werden. Dazu muß das Hologramm mit kohärenter Strahlung beleuchtet werden. Dies kann numerisch mit einem Rekonstruktionsalgorithmus beruhend auf der Kirchhoff-Helmholtz-Transformation erfolgen. Die zur Rekonstruktion verwendete Software LEEPS bietet auch die Möglichkeit, Hologramme zu simulieren, mit denen die Abbildungen im Elektronen-Projektionsmikroskop verglichen werden können. Phthalocyaninatopolysioloxan, DNA und das cis-Platin-Addukt an DNA wurden auf unterschiedlichen Objektträgern präpariert und holographisch abgebildet. Die Hologramme der stäbchenförmigen Moleküle rekonstruieren als Stränge mit einem Durchmesser von ca. 2 nm, was sehr gut dem Moleküldurchmesser entspricht. Die Doppelhelix der DNA konnte ebenfalls aufgelöst werden. Die zu den Experimenten durchgeführten Simulationen bestätigten die experimentellen Ergebnisse. Weitere Simulationen zeigten, daß bei Verwendung eines größeren Bildschirms und höherer Energie eine Auflösung im Subnanometer-Bereich möglich sein sollte

About the proof-theoretic ordinals of weak fixed point theories

This paper presents several proof-theoretic results concerning weak fixed point theories over second order number theory with arithmetic comprehension and full or restricted induction on the natural numbers. It is also shown that there are natural second order theories which are proof-theoretically equivalent but have different proof-theoretic ordinal

KULTURNI TURIZAM KAO KONKURENTNI ČIMBENIK U MEDITERANSKOM TURIZMU - Komparativna studija japanskog i njemačkog izvornog tržišta za talijansku kulturnu baštinu

The Mediterranean region is a delicate area of living, exposed to severe trouble that may be caused even by minor influences, e.g. military conflicts. Therefore, it is necessary to search for useful long-term solutions for tourism in the countries of this region. Due to the abundance of cultural assets, cultural tourism becomes ever more important. On the other hand, the weak points of product development and marketing become apparent in spite of great demand. This empirical study determines the needs of people potentially interested in visiting Italy with the example of the source markets in Japan and in Germany, particularly considering cultural tourism with specific consideration of castles and stately homes. Having determined these needs, it will be possible to show the required consequences for product development and marketing at a local, regional, national and international level.Mediteran je osjetljivo područje za život, izloženo ozbiljnom problemu koji može biti izazvan i neznatnim utjecajem npr. vojnim konfliktima. Zbog toga je potrebno tražiti korisna dugoročna rješenja za turizam u zemljama tog područja. Zbog obilja kulturnog bogatstva kulturni turizam postaje još važniji. S druge strane, slabe točke razvoja proizvoda i marketinga bivaju očevidni unatoč velikoj potražnji. Ova empirijska studija utvrđuje potrebe ljudi, potencijalno zainteresiranih da posjete Italiju s primjerom izvornih tržišta Japana i Njemačke, osobito u svezi kulturnog turizma sa specifičnim naglaskom dvoraca i otmjenih obiteljskih kuća. Nakon što smo utvrdili te potrebe biti će moguće pokazati potrebna djelovanja za razvoj proizvoda i marketinga na lokalnoj, područnoj, nacionalnoj i međunarodnoj razini

Next-to-leading order QCD corrections to Z boson pair production via vector-boson fusion

Vector-boson fusion processes are an important tool for the study of electroweak symmetry breaking at hadron colliders, since they allow to distinguish a light Higgs boson scenario from strong weak boson scattering. We here consider the channels WW->ZZ and ZZ->ZZ as part of electroweak Z boson pair production in association with two tagging jets. We present the calculation of the NLO QCD corrections to the cross sections for p p -> e+ e- mu+ mu- + 2 jets and p p -> e+ e- nu_mu nubar_mu + 2 jets via vector-boson fusion at order alpha_s alpha^6, which is performed in the form a NLO parton-level Monte Carlo program. The corrections to the integrated cross sections are found to be modest, while the shapes of some kinematical distributions change appreciably at NLO. Residual scale uncertainties typically are at the few percent level.Comment: 12 pages, 4 figure

Parton-shower effects in Higgs production via Vector-Boson Fusion

We present a systematic investigation of parton-shower and matching perturbative uncertainties for Higgs-boson production via vector-boson fusion. To this end we employ different generators at next-to-leading order QCD accuracy matched with shower Monte Carlo programs, PYTHIA8, and HERWIG7, and a next-to-next-to-leading order QCD calculation. We thoroughly analyse the intrinsic sources of uncertainty within each generator, and then compare predictions among the different tools using the respective recommended setups. Within typical vector-boson fusion cuts, the resulting uncertainties on observables that are accurate to next-to-leading order are at the 10% level for rates and even smaller for shapes. For observables sensitive to extra radiation effects uncertainties of about 20% are found. We furthermore show how a specific recoil scheme is needed when PYTHIA8 is employed, in order not to encounter unphysical enhancements for these observables. We conclude that for vector-boson fusion processes an assessment of the uncertainties associated with simulation at next-to-leading order matched to parton showers based only on the variation of renormalisation, factorisation and shower scales systematically underestimates their true size.Comment: v2 matches the version published on EPJ

QCD Corrections to Vector-Boson Fusion Processes in Warped Higgsless Models

We discuss the signatures of a representative Higgsless model with ideal fermion delocalization in vector-boson fusion processes, focusing on the gold- and silver-plated decay modes of the gauge bosons at the CERN-Large Hadron Collider. For this purpose, we have developed a fully-flexible parton-level Monte-Carlo program, which allows for the calculation of cross sections and kinematic distributions within experimentally feasible selection cuts at NLO-QCD accuracy. We find that Kaluza-Klein resonances give rise to very distinctive distributions of the decay leptons. Similar to the Standard Model case, within the Higgsless scenario the perturbative treatment of the vector-boson scattering processes is under excellent control.Comment: 22 pages, 20 figure